A Browser Theme is a special kind of extension that changes the way the browser looks.¬†Themes are packaged like regular extensions, but they don’t contain JavaScript or HTML code.

You can find and try a bunch of themes at the Chrome Web Store. Most of the browser allow users to use themes to improve the look and the feel of the web browser.

Links for Mozilla Firefox Themes

Just search online for a theme if you would like to change your theme.